Methods for covering a portion of a fastener protruding from a surface

ABSTRACT

A cap for use in covering a portion of a fastener protruding from a surface is provided. The portion includes threads. The cap includes an interior, a base that at least partially delimits the interior, a threaded receptacle on the interior configured to threadably engage the portion of the fastener, and a seal coupled to the base to engage the surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation and claims priority to U.S. patentapplication Ser. No. 14/034,140 filed Sep. 23, 2013 now U.S. Pat. No.9,618,029 B2 for “SYSTEMS AND METHODS FOR USE IN COVERING A PORTION OF AFASTENER PROTRUDING FROM A SURFACE”, and issued as U.S. Pat. No.9,618,029 on Apr. 11, 2017, which is hereby incorporated by reference inits entirety.

BACKGROUND

Various structures are assembled using a plurality of fasteners. Someprotruding fasteners may need to be covered with insulating caps thatrequire internal and external application of sealant to inhibitelectromagnetic energy and/or hot particles from being discharged fromthe fasteners. Existing methodologies of covering protruding fastenerswith caps requiring application of sealant are labor-intensive andtime-consuming.

SUMMARY

Accordingly, systems and methods for use in covering a portion of afastener protruding from a surface, intended to address theabove-identified concerns, would find utility.

One example of the present disclosure relates to a system for use incovering a portion of a fastener protruding from a surface. The systemincludes a cap that includes an interior, a base that at least partiallydelimits the interior, and pawls on the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes a tooth configured to be associatedwith the fastener and configured to positively engage the pawls.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth includes a tapered surface facing away from a head ofthe fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth is configured to threadably engage the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes a nut configured to be coupled to thefastener, wherein the nut includes the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth is delimited on one side by a groove formed in anouter surface of the nut.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes a collar configured to be coupled tothe fastener and a retainer configured to couple the collar to thefastener. In this aspect, the collar includes the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth is configured to be coupled to the fastener with aninterference fit.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth is integrally formed with the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth and the surface are separated by a space.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tooth positively engages the pawls is configured to beloaded in compression against the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, each of the pawls includes a first end proximal to the base anda second end distal from the base.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the second end has a greater width than the first end.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the pawls are configured to be loaded in tension against thetooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, each of the pawls includes a first end distal from the base anda second end extending toward the base.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap also includes a seal coupled to the base to engage thesurface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the seal is configured to bias the pawls against the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap also includes a wall that at least partially delimitsthe interior and at least one port that extends through the wall.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port includes an injection port configured toreceive sealant therethrough and a bleed port configured to allow air toescape from the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the injection port has a larger diameter than a diameter of thebleed port.

One example of the present disclosure relates to a method that includesproviding a fastener that includes a tooth. A portion of the fastenerprotrudes from a surface. The method also includes providing a cap thatincludes a wall, a base, an interior at least partially delimited by thewall and the base, and pawls on the interior; covering the portion ofthe fastener with the cap; and positively engaging the pawls with thetooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, positively engaging the pawls with the tooth includes loadingthe pawls in compression against the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects positively engaging the pawls with the tooth includes loadingthe pawls in tension against the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, positively engaging the pawls with the tooth includeselastically deforming the pawls relative to the tooth prior topositively engaging the pawls with the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, positively engaging the pawls with the tooth includes biasingthe pawls against the tooth.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, providing the fastener that includes the tooth includescoupling the tooth to the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, coupling the tooth to the fastener includes threadably engagingthe tooth with the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, coupling the tooth to the fastener includes coupling the toothto the fastener with a retainer.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, coupling the tooth to the fastener includes locating the toothproximal to the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, coupling the tooth to the fastener includes locating the toothdistal from the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, providing the fastener that includes the tooth includesintegrally forming the tooth with the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap includes at least one port extending through the wall.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port is a single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,creating a vacuum in the interior, and injecting a sealant into theinterior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, creating the vacuum in the interior includes withdrawing airfrom the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a sealant includes injecting a predetermined amountof sealant into the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a predetermined amount of sealant includesdetermining the predetermined amount of sealant based on a vacant volumeof the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes discontinuing to inject the sealantupon detection of a predetermined back pressure at single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,injecting a sealant into the interior through the at least one port, andallowing air to escape from the interior through the at least one port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port includes an injection port and a bleedport.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the sealant is injected into the interior through the injectionport and the air escapes from the interior through the bleed port.

One example of the present disclosure relates to a method of packaging acap for use in covering a portion of a fastener protruding from asurface. The cap includes an interior having a surface. The methodincludes providing the cap that is generally clean to facilitateadhesion of a sealant to the interior surface and encapsulating at leasta portion of the cap.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, encapsulating at least a portion of the cap includesencapsulating the interior of the cap.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, encapsulating the interior of the cap includes providing thecap with a base that at least partially delimits the interior andcoupling a film seal to the base,

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, encapsulating at least a portion of the cap includesencapsulating the cap entirely within a sealed container.

One example of the present disclosure relates to a system for use incovering a portion of a fastener selected from fasteners protruding fromsurfaces in a plurality of orientations. The system includes collectionsof caps. Each collection is associated with one of the plurality oforientations. The caps in each collection differ from the caps in othercollections in at least one feature.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one feature includes a location of at least oneport formed in each of the caps.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, a unique identifier is associated with each collection of caps.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the unique identifier is a color.

One example of the present disclosure relates to a method of covering aportion of a fastener selected from fasteners protruding from surfacesin a plurality of orientations. The method includes providingcollections of caps with each collection associated with one of theplurality of orientations. The caps in each collection differ from thecaps in other collections in at least one feature. The method alsoincludes determining an orientation of the fastener, selecting a capfrom a collection of caps associated with the orientation of thefastener, and covering the portion of the fastener with the cap.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, covering the portion of the fastener with the cap includespositively engaging the cap with the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes associating each collection of capswith a unique identifier.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the unique identifier is a color.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the unique identifier is packaging.

One example of the present disclosure relates to a cap for use incovering a portion of a fastener protruding from a surface. The portionincludes threads. The cap includes an interior, a base that at leastpartially delimits the interior, a threaded receptacle on the interiorconfigured to threadably engage the portion of the fastener, and a sealcoupled to the base to engage the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap also includes an exterior partially delimited by thebase and having a shape configured to be operable with a tool.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the exterior includes at least one flat surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the exterior includes at least one projection.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the base has a larger profile than a remainder of the cap.

One example of the present disclosure relates to a method of covering aportion of a fastener protruding from a surface. The portion includesthreads. The method includes providing a cap that includes a wall, abase, an interior at least partially delimited by the wall and the base,and a threaded receptacle on the interior; threadably engaging thethreaded receptacle with the portion of the fastener; and sealing thebase of the cap against the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap includes at least one port extending through the wall.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port is a single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,creating a vacuum in the interior, and injecting a sealant into theinterior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, creating the vacuum in the interior includes withdrawing airfrom the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a sealant includes injecting a predetermined amountof sealant into the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a predetermined amount of sealant includesdetermining the predetermined amount of sealant based on a vacant volumeof the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes discontinuing to inject the sealantupon detection of a predetermined back pressure at single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,injecting a sealant into the interior through the at least one port, andallowing air to escape from the interior through the at least one port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port includes an injection port and a bleedport.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the sealant is injected into the interior through the injectionport and the air escapes from the interior through the bleed port.

One example of the present disclosure relates to a system for use incovering a portion of a fastener protruding from a surface. The systemincludes a cap that includes an interior, a base that at least partiallydelimits the interior, and at least one cam on the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes at least one tab coupled to thefastener to engage the at least one cam.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes a collar configured to be coupled tothe fastener. The collar includes the at least one tab.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the system also includes a retainer configured to couple thecollar to the fastener.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one tab is spaced a distance from the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one tab is angled away from the surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one cam includes a plurality of cams.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one cam extends from a surface of the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one cam is recessed in a surface of the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one cam has a tapered surface.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the tapered surface faces away from the base of the cap.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one cam includes a notch to positively engage theat least one tab.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap also includes a wall that at least partially delimitsthe interior and at least one port that extends through the wall.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port includes an injection port configured toreceive sealant therethrough and a bleed port configured to allow air toescape from the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap also includes a seal coupled to the base to engage thesurface.

One example of the present disclosure relates to a method of covering aportion of a fastener protruding from a surface. The method includesproviding a cap that includes a wall, an interior at least partiallydelimited by the wall, and at least one cam on the interior. The methodalso includes coupling at least one tab with the fastener, covering theportion of the fastener with the cap, and rotating the cap to engage theat least one cam with the at least one tab.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, rotating the cap includes positively engaging the at least onecam with the at least one tab.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the cap includes at least one port extending through the wall.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port is a single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,creating a vacuum in the interior, and injecting a sealant into theinterior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, creating the vacuum in the interior includes withdrawing airfrom the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a sealant includes injecting a predetermined amountof sealant into the interior through the single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, injecting a predetermined amount of sealant includesdetermining the predetermined amount of sealant based on a vacant volumeof the interior.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes discontinuing to inject the sealantupon detection of a predetermined back pressure at single port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the method also includes sealing the base against the surface,injecting a sealant into the interior through the at least one port, andallowing air to escape from the interior through the at least one port.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the at least one port includes an injection port and a bleedport.

In one aspect of the disclosure, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples andaspects, the sealant is injected into the interior through the injectionport and the air escapes from the interior through the bleed port.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of an illustrative aircraft production andservice methodology.

FIG. 2 is a block diagram of an illustrative aircraft.

FIG. 3 is a schematic illustration of an aircraft assembly including afastener whose protruding portion is covered using a system according toan aspect of the present disclosure.

FIG. 4 is a block diagram of a system for use in covering a protrudingportion of a fastener, such as that illustrated in FIG. 3, according toone aspect of the disclosure.

FIG. 5 is a perspective sectional view of a system for use in covering aprotruding fastener, according to one aspect of the disclosure.

FIG. 6 is a perspective view of a cap that may be used with the systemshown in FIG. 5, according to one aspect of the disclosure.

FIG. 7 is a perspective sectional view of the cap shown in FIG. 6.

FIG. 8 is a perspective view of a tooth that may be used with the systemshown in FIG. 5, according to one aspect of the disclosure.

FIG. 9 is a perspective sectional view of a cap of a system for use incovering a protruding fastener, according to one aspect of thedisclosure.

FIG. 10 is a perspective sectional view of a system for use in coveringa protruding fastener, according to one aspect of the disclosure.

FIG. 11 is a perspective view of a tooth that may be used with thesystem shown in FIG. 10.

FIG. 12 is a perspective sectional view of a system for use in coveringa protruding fastener, according to one aspect of the disclosure.

FIG. 13 is a perspective view of a cap that may be used with the systemshown in FIG. 12, according to one aspect of the disclosure.

FIG. 14 is a perspective view of a tooth that may be used with thesystem shown in FIG. 12, according to one aspect of the disclosure.

FIG. 15 is a block diagram of a cap that may be used to cover a portionof the fastener shown in FIG. 3, according to one aspect of thedisclosure.

FIG. 16 is a perspective sectional view of a cap according to one aspectof the disclosure.

FIG. 17 is a perspective view of the cap shown in FIG. 16.

FIG. 18 is a perspective bottom view of the cap shown in FIG. 17.

FIG. 19 is a block diagram of a system that may be used to cover aportion of the fastener shown in FIG. 3.

FIG. 20 is a perspective sectional view of an illustrative system ofFIG. 19, according to one aspect of the disclosure.

FIG. 21 is a perspective bottom view of the system shown in FIG. 20,according to one aspect of the disclosure.

FIG. 22 is a perspective sectional view of a cap that may be used withthe system shown in FIG. 20, according to one aspect of the disclosure.

FIG. 23 is a perspective sectional view of an alternative cap that maybe used with the system shown in FIG. 20, according to one aspect of thedisclosure.

FIG. 24 is a perspective sectional view of an alternative system inaccordance with FIG. 19, according to one aspect of the disclosure.

FIG. 25 is a perspective bottom view of the system shown in FIG. 24.

FIG. 26 is a perspective sectional view of the cap shown in FIG. 25.

FIG. 27 is a flow diagram of an exemplary method method of covering aportion of a fastener protruding from a surface.

FIG. 28 is a flow diagram of an exemplary method of packaging a cap foruse in covering a portion of a fastener protruding from a surface.

FIG. 29 is a flow diagram of an exemplary method of covering a portionof a fastener selected from fasteners protruding from surfaces in aplurality of orientations.

FIG. 30 is a flow diagram of an alternative exemplary method of coveringa portion of a fastener protruding from a surface.

DETAILED DESCRIPTION

The implementations described herein relate to systems and methods thatfacilitate covering portions of fasteners protruding from a surface withcaps. More specifically, the systems, according to the various aspectsof the disclosure, include one or more features that enable the caps tobe positively engaged with the fasteners, such that the caps may be moreeasily installed over the fasteners. In some aspects, the caps may alsoinclude features that enable sealant to be injected inside the capsafter installation thereof over the fasteners, and features that enablethe caps to be removed and/or replaced with a tool. As such, the systemsdescribed herein may enable automated installation of caps overfasteners to facilitate reducing manufacturing times of associatedassemblies.

Referring to the drawings, implementations of the disclosure may bedescribed in the context of an aircraft manufacturing and service method100 (shown in FIG. 1) and via an aircraft 102 (shown in FIG. 2). Duringpre-production, including specification and design 104 data of aircraft102 may be used during the manufacturing process and other materialsassociated with the airframe may be procured 106. During production,component and subassembly manufacturing 108 and system integration 110of the aircraft 102 occurs, prior to aircraft 102 entering itscertification and delivery process 112. Upon successful satisfaction andcompletion of airframe certification, aircraft 102 may be placed inservice 114. While in service by a customer, aircraft 102 is scheduledfor periodic, routine, and scheduled maintenance and service 116,including any modification, reconfiguration, and/or refurbishment, forexample.

Each portion and process associated with aircraft manufacturing and/orservice 100 may be performed or completed by a system integrator, athird party, and/or an operator (e.g., a customer). For the purposes ofthis description, a system integrator may include without limitation anynumber of aircraft manufacturers and major-system subcontractors; athird party may include without limitation any number of venders,subcontractors, and suppliers; and an operator may be an airline,leasing company, military entity, service organization, and so on.

As shown in FIG. 2, an aircraft 102 produced via method 100 may includean airframe 118 having a plurality of systems 120 and an interior 122.Examples of high-level systems 120 include one or more of a propulsionsystem 124, an electrical system 126, a hydraulic system 128, and/or anenvironmental system 130. Any number of other systems may be included.Although an aircraft example is shown, the principles of the inventionmay be applied to non-aviation industries, such as the automotiveindustry.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of method 100. For example, components orsubassemblies corresponding to component production process 108 may befabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 102 is in service. Also, one ormore apparatus implementations, method implementations, or a combinationthereof may be utilized during the production stages 108 and 110, forexample, by substantially expediting assembly of, and/or reducing thecost of assembly of aircraft 102. Similarly, one or more of apparatusimplementations, method implementations, or a combination thereof may beutilized while aircraft 102 is being serviced or maintained, forexample, during scheduled maintenance and service 116.

As used herein, the term “aircraft” may include, but is not limited to,airplanes, unmanned aerial vehicles (UAVs), gliders, helicopters, and/orany other object that travels through airspace.

FIG. 3 is a schematic illustration of an illustrative aircraft assembly200 that may be associated with aircraft 102. Aircraft assembly 200includes an outer skin 202, a stringer 204, and a fastener 210 extendingthrough outer skin 202 and stringer 204. A portion 212 of fastener 210protrudes from a surface 206 of stringer 204 into an interior 208 ofaircraft assembly 200. In one implementation, interior 208 is configuredto store fuel (not shown) therein. As such, portion 212 is covered usinga system 220 to facilitate inhibiting electromagnetic discharge and/orhot particle ejection from fastener 210 and to facilitate preventingignition of the fuel in interior 208.

Referring to FIGS. 4-14, one example of the disclosure relates to system220 for use in covering portion 212 of fastener 210 (shown in FIG. 3).System 220 includes a tooth 230 and a cap 250. Cap 250 includes aninterior 252, an exterior 254, a wall 256, a base 258, and a seal 260coupled to base 258. Interior 252 is at least partially delimited bywall 256 and base 258. Interior 252 further includes a surface 262 andpawls 264 on surface 262 that positively engage tooth 230. As usedherein, the terms “positively engage” and/or “positive engagement” meansrequiring more force to remove than to install. Moreover, tooth 230includes a tapered surface 232, and at least one port 270 is formed inwall 256.

In FIG. 4, lines connecting various elements and/or components of system220 may represent mechanical, electrical, fluid, optical,electromagnetic and other couplings and/or combinations thereof.Couplings other than those depicted in FIG. 4 may also exist. Dashedlines connecting the various elements and/or components of system 220may represent couplings similar in function and purpose to thoserepresented by solid lines; however, couplings represented by the dashedlines are either selectively provided or relate to alternative oroptional aspects of the disclosure. Likewise, elements and/or componentsof system 220 represented in dashed lines represent alternative oroptional aspects of the disclosure.

Referring, e.g. to FIGS. 4-8, system 220 includes cap 250 that includesinterior 252, base 258 that at least partially delimits interior 252,and pawls 264 on interior 252. In one aspect, system 220 also includestooth 230 configured to be associated with fastener 210 and configuredto positively engage pawls 264. In one aspect, tooth 230 includestapered surface 232 (e.g., FIG. 3) facing away from a head 214 offastener 210. In operation, tapered surface 232 enables pawls 264 toreadily slide into positive engagement with tooth 230 as cap 250 coversportion 212 of fastener 210.

Referring to FIGS. 8 and 11, in one aspect, tooth 230 is configured tothreadably engage fastener 210. Referring to FIG. 8, system 220 alsoincludes a nut 280 configured to be coupled to fastener 210. Nut 280includes tooth 230. In one aspect, tooth 230 is delimited on one side bya groove 282 formed in an outer surface 284 of nut 280. Alternatively,tooth 230 may be configured to be coupled to fastener 210 with aninterference fit, or may be integrally formed with fastener 210.

Referring to FIG. 5, in one aspect, tooth 230 positively engages pawls264 that are configured to be loaded in compression against tooth 230.In one aspect, pawls 264 are spaced circumferentially about interior252, and each of pawls 264 includes a first end 266 proximal to base 258and a second end 268 distal from base 258. For example, first end 266may be coupled to surface 262 of interior 252. Referring to FIG. 9, inone aspect, second end 268 has a greater width than first end 266. Assuch, the greater width of second end 268 facilitates reducing thenumber of pawls 264 required to extend substantially circumferentiallyabout interior 252 of cap 250.

Pawls 264 may be made of any material that enables system 220 tofunction as described herein. More specifically, pawls 264 may be madeof a flexible material to enable pawls 264 to elastically deform as cap250 covers portion 212 of fastener 210 to facilitate engagement of tooth230 and pawls 264. For example, pawls 264 may elastically deformradially outward from fastener 210 as cap 250 covers portion 212 offastener 210. As such, the material and dimensions of pawls 264 areselected to enable the pawls to elastically deform in directionsgenerally transverse to their longitudinal axes and yet to provide pawls264 with sufficient axial stiffness to promote positive engagement ofpawls 264 and tooth 210.

Referring to FIGS. 10 and 12, in one aspect, cap 250 also includes wall256 that at least partially delimits interior 252, and at least one port270 that extends through wall 256. In one aspect, the at least one port270 includes an injection port 272 configured to receive sealant (notshown) therethrough and a bleed port 274 configured to allow air toescape from interior 252. Bleed port 274 enables the sealant tosubstantially fill interior 252 by limiting the formation of air pocketsin interior 252. In one aspect, injection port 272 has a larger diameterthan a diameter of bleed port 274. As such, the smaller diameter ofbleed port 274 facilitates restricting sealant from being dischargedtherethrough as sealant is injected into and substantially fillsinterior 252. In an alternative implementation, wall 256 issubstantially solid and does not include at least one port 270.

Cap 250 is also configured to facilitate inhibiting electromagneticdischarge and/or hot particle ejection from fastener 210 and intointerior 210 of aircraft assembly 200 (shown in FIG. 3). For example,cap 250 may be formed from an electrically non-conductive material.Exemplary materials include, but are not limited to, a nylon material, aglass-filled nylon material, an epoxy material, and a glass-filled epoxymaterial. Further, the sealant injected into interior 252 of cap 250 anda thickness of wall 256 facilitates electrically insulating fastener210. In an alternative implementation, the thickness of wall 256 may beselected and/or increased such that sealant may not be required toelectrically insulate fastener 210. Exterior 254 of cap 250 may alsohave a convex shape, and/or may have a length to diameter ratio of lessthan about 3 to 1 to facilitate inhibiting electromagnetic dischargefrom fastener 210.

As described above, in one aspect, seal 260 is coupled to base 258 toengage surface 206 (shown in FIG. 3). Seal 260 may be monolithic withbase 258, or may be separate from base 258 as shown in FIGS. 5, 10, and12. Referring, e.g., to FIG. 9, in one aspect, seal 260 is receivedwithin a channel 261 formed in base 258. Alternatively, seal 260 may becoupled to base 258 by another suitable coupling mechanism and/or anadhesive.

Referring, e.g., to FIG. 3, in one aspect, seal 260 is also configuredto bias pawls 264 against tooth 230. More specifically, in operation,seal 260 may be compressed between base 258 and surface 206 as cap 250is installed to cover portion 212 of fastener 210. For example, duringinstallation of cap 250, a force may be applied to cap 250 compressingseal 260 against surface 206 to enable engagement between between secondend 268 of pawls 264 and tooth 230. After the force has been removed,seal 260 expands to bias cap 250 in a direction away from surface 206such and pawls 264 positively engage tooth 230. Seal 260 remains atleast partially compressed such that cap 250 may be sealed againstsurface 206.

Seal 260 may be made of any material that enables system 220 to functionas described herein. More specifically, seal 260 may be made of amaterial able to withstand prolonged use in a fuel-rich environment, andcapable of maintaining its elasticity in a compressed state. Anexemplary material includes, but is not limited to, a fluorosiliconematerial.

Referring to FIGS. 10-14, in one aspect, system 220 includes a collar286 configured to be coupled to fastener 210, wherein collar 286includes tooth 230. In FIGS. 12-14, in one aspect, system 220 alsoincludes a retainer 288 configured to couple collar 286 to fastener 210.More specifically, retainer 288 is coupled to portion 212 of fastener210 with an interference fit to facilitate restricting movement ofcollar 286 along longitudinal axis 218 of fastener 210. System 220 alsoincludes a spacer 290 positioned between collar 286 and surface 206(shown in FIG. 3) such that, in one aspect, tooth 230 and surface 206are separated by a space to facilitate engagement of pawls 264 and tooth230.

Referring again to FIGS. 12-14, in one aspect, pawls 264 are configuredto be loaded in tension against tooth 230. More specifically, in oneaspect, pawls 264 include first end 266 distal from base 258 and secondend 268 extending towards base 258 to positively engage tooth 230. Forexample, at least a portion of second end 268 extends towards base 258to be located in the space between tooth 230 and surface 206 (FIG. 3),and to be biased into engagement with an underside of tooth 230. Assuch, spacer 290 has any thickness that enables pawls 264 to positivelyengage tooth 230.

A method (shown in FIG. 27) of covering portion 212 of fastener 210protruding from surface 206 is also provided. The method includesproviding 330 fastener 210 that includes tooth 230 and providing 332 cap250 that includes wall 256, base 258, interior 252 at least partiallydelimited by wall 256 and base 258, and pawls 264 on interior 252. Themethod also includes covering 334 portion 212 of fastener 210 with cap250, and positively engaging 336 pawls 264 with tooth 230.

In some aspects, the pawls 264 are either loaded in compression againsttooth 230, or loaded in tension against tooth 230 to be positivelyengaged therewith. Further, in one aspect and as described above,positively engaging pawls 264 with tooth 230 includes elasticallydeforming pawls 264 relative to tooth 230 prior to positively engagingpawls 264 with tooth 230. In one aspect, positively engaging pawls 264with tooth 230 also includes biasing pawls 264 against tooth 230 usingseal 260.

In one aspect, providing fastener 210 that includes tooth 230 includeseither coupling tooth 230 to fastener 210, or integrally forming tooth230 with fastener 210. In one aspect, coupling tooth 230 to fastener 210includes threadably engaging tooth 230 with fastener 210, or couplingtooth 230 to fastener 210 with retainer 288. Moreover, in one aspect,coupling tooth 230 to fastener 210 also includes locating tooth 230proximal to surface 206, or locating tooth 230 distal from surface 206.More specifically, the location of tooth 230 is selected based onwhether pawls 264 are to be loaded in compression or tension againsttooth 230. For example, tooth 230 is located distal to surface 206 whenpawls 264 are to be loaded in compression against tooth 230.Alternatively, tooth 230 may be located proximal to surface 206 whenpawls 264 are to be loaded in tension against tooth 230.

As described above, in one aspect, cap 250 includes at least one port270 extending through wall 256. In one aspect, the at least one port 270may be a single port. In one aspect, the method also includes sealingbase 258 against surface 206, creating a vacuum in interior 252, andinjecting a sealant into interior 252. In one aspect, creating thevacuum in interior 252 includes withdrawing air from interior 252through the single port. As such, withdrawing air from interior 252enables the sealant to substantially fill interior 252 by limiting theformation of air pockets in interior 252.

In one implementation, an amount of sealant to be injected into interior252 may be selected to prevent the use of excess sealant, to facilitatecleanup, and to promote a reduction in the weight of aircraft 102 (shownin FIG. 2). As such, in one aspect, injecting the sealant includesinjecting a predetermined amount of sealant into interior 252 throughthe single port. More specifically, in one aspect, injecting apredetermined amount of sealant includes determining the predeterminedamount of sealant for filling interior 252 based on a vacant volume ofinterior 252. In one aspect, the use of excess sealant is avoided bydiscontinuing to inject the sealant upon detection of a predeterminedback pressure at the single port. The predetermined back pressure may beany suitable pressure selected to indicate that interior 252 has beensubstantially filled with sealant.

Alternatively, in one aspect, the method includes sealing base 258against surface 206, injecting a sealant into interior 252 through theat least one port 270, and allowing air to escape from interior 252through the at least one port 270. In one aspect, the at least one portincludes injection port 272 and bleed port 274, and the sealant isinjected into interior 252 through injection port 272 and the airescapes from interior 252 through bleed port 274. The sealant is thenallowed to cure to facilitate coupling cap 250 to fastener 210.

A method (shown in FIG. 28) of packaging cap 250 for use in coveringportion 212 of fastener 210 protruding from surface 206 is alsoprovided. Cap 250 includes interior 252 having surface 262. The methodincludes providing 338 cap 250 that is generally clean to facilitateadhesion of a sealant to interior surface 262, and encapsulating 340 atleast a portion of cap 250. Cap 250 may be generally clean because cap250 may be manufactured in a clean environment, and/or because interiorsurface 262 may be cleaned after cap 250 is manufactured.

In one aspect, encapsulating 340 at least a portion of cap 250 includesencapsulating interior 252 of cap 250, or encapsulating cap 250 entirelywithin a sealed container (not shown). More specifically, in one aspect,encapsulating interior 252 of cap 250 includes providing cap 250 withbase 258 that at least partially delimits interior 252, and coupling afilm seal 259 (shown in FIG. 4) to base 258. As such, encapsulating 340cap 250 facilitates restricting exposure of cap 250 to contaminationthat may reduce adhesion of the sealant to interior surface 262.Encapsulating 340 cap 250 also facilitates reducing cap installationtime by enabling a user to install cap 250 over fastener 210 withouthaving to clean cap 250 after removing it from associated packaging.

One example of the present disclosure relates to a system for use incovering portion 212 of fastener 210 selected from fasteners protrudingfrom surfaces in a plurality of orientations. The system includescollections of caps. Each collection is associated with one of theplurality of orientations, and the caps in each collection differ fromthe caps in other collections in at least one feature. In one aspect,the at least one feature may include a location of at least one portformed in each of the caps. The at least one port may include injectionport 272 and bleed port 274 formed in different locations in cap 250based on an orientation of the fastener to be covered. Morespecifically, the location of injection port 272 and bleed port 274 maybe selected to facilitate limiting the formation of air pockets ininterior 252 as sealant is injected into interior 252. For example, whencap 250 is installed, the smaller diameter bleed port 274 may be locatedat a higher relative elevation than injection port 272. As such, bleedport 274 remains substantially unblocked to allow air to escape frominterior 252 therethrough as sealant is injected through injection port272. Alternatively, the at least one port is a single injection port 272located in cap 250 at a lower relative elevation than a remainder of cap250.

In one aspect, a unique identifier is associated with each collection ofcaps to enable a user to easily identify which collection of caps shouldbe used to cover a fastener protruding from a surface in a determinedorientation. In one aspect, the unique identifier may be a color, and/ormay be packaging associated with each collection of caps. Morespecifically, a different color may be associated with each collectionof caps, and may be associated with the material used to form the capsand/or associated with the packaging for the caps.

Referring to FIG. 30, in one aspect, a system 350 includes a firstcollection 352 a of caps and a second collection 352 b of caps.Collections 352 a and 352 b are for covering fasteners protruding fromsurfaces in a plurality of orientations, and each collection isassociated with one of the plurality of orientations. In one aspect,first collection 352 a includes a first cap 250 a and a second cap 250b, and second collection 352 b includes a first cap 250 c and a secondcap 250 d. A unique identifier is associated with each collection. Morespecifically, a first unique identifier 354 a is associated with firstcollection 352 a, and a second unique identifier 354 b is associatedwith second collection 352 b. As such, in one aspect, caps 250 a and 250b of first collection 352 a each include first unique identifier 354 a,and caps 250 c and 250 d of second collection 352 b each include secondunique identifier 354 b.

A method (shown in FIG. 29) of covering a portion of a fastener selectedfrom fasteners protruding from surfaces in a plurality of orientationsis also provided. The method includes providing 342 collections of caps250, wherein each collection is associated with one of the plurality oforientations of the fasteners. As described above, the caps 250 in eachcollection differ from the caps in other collections in at least onefeature. The method also includes determining 344 an orientation of thefastener 210, selecting 346 a cap 250 from a collection of caps 250associated with the orientation of the fastener 210, and covering 348the portion 212 of the fastener 210 with the cap 250.

Referring to FIGS. 15-18, one example of the disclosure relates to cap250 for use in covering portion 212 of fastener 210 protruding fromsurface 206 (shown in FIG. 3). Portion 212 includes threads 216 (shownin FIG. 3). Cap 250 includes interior 252, base 258 that at leastpartially delimits interior 252, a threaded receptacle 292 on interior252 configured to threadably engage portion 212 of fastener 210, andseal 260 coupled to base 258 to engage surface 206.

In FIG. 15, lines connecting various elements and/or components of cap250 may represent mechanical, electrical, fluid, optical,electromagnetic and other couplings and/or combinations thereof.Couplings other than those depicted in FIG. 15 may also exist. Dashedlines connecting the various elements and/or components of cap 250 mayrepresent couplings similar in function and purpose to those representedby solid lines; however, couplings represented by the dashed lines areeither selectively provided or relate to alternative or optional aspectsof the disclosure. Likewise, elements and/or components of cap 250represented in dashed lines represent alternative or optional aspects ofthe disclosure.

Referring to FIGS. 16-18 and 21, in one aspect, cap 250 includesexterior 254 that is partially delimited by base 258 and having a shapeconfigured to be operable with a tool (not shown). More specifically,the shape of exterior 254 may have one or more features that enable thetool to engage and rotate cap 250 about longitudinal axis 218 such thatthreaded receptacle 292 may threadably engage threads 216 of fastener210. For example, in one aspect and referring to FIG. 17, the feature(s)include at least one flat surface 255. In another aspect and referringto FIG. 21, such feature(s) include at least one projection 257. In oneaspect, base 258 may also have a larger cross-sectional profile than aremainder of cap 250 to provide a lip for the tool to press against andforce cap 250 towards surface 206 when covering fastener 210.

A method of covering portion 212 of fastener 210 protruding from surface206 is also provided. Portion 212 includes threads 216. The methodincludes providing cap 250 that includes wall 256, base 258, interior252 at least partially delimited by wall 256 and base 258, and threadedreceptacle 292 on interior 252, threadably engaging threaded receptacle292 with portion 212 of fastener 210, and sealing base 258 of cap 250against surface 206.

As described above, in one aspect, cap 250 includes at least one port270 extending through wall 256. In one aspect, the at least one port 270may be a single port. In one aspect, the method further includes sealingbase 258 against surface 206, creating a vacuum in interior 252, andinjecting a sealant into interior 252. In one aspect, creating thevacuum in interior 252 includes withdrawing air from interior 252through the single port. As such, withdrawing air from interior 252enables the sealant to substantially fill interior 252 by limiting theformation of air pockets in interior 252.

In one implementation, an amount of sealant to be injected into interior252 may be selected to prevent the use of excess sealant, to facilitatecleanup, and to promote a reduction in the weight of aircraft 102 (shownin FIG. 2). As such, in one aspect, injecting the sealant includesinjecting a predetermined amount of sealant into interior 252 throughthe single port. More specifically, in one aspect, injecting apredetermined amount of sealant includes determining the predeterminedamount of sealant for filling interior 252 based on a vacant volume ofinterior 252. In one aspect, the use of excess sealant is avoided bydiscontinuing to inject the sealant upon detection of a predeterminedback pressure at the single port. The predetermined back pressure may beany suitable pressure selected to indicate that interior 252 has beensubstantially filled with sealant.

Alternatively, in one aspect, the method includes sealing base 258against surface 206, injecting a sealant into interior 252 through theat least one port 270, and allowing air to escape from interior 252through the at least one port 270. In one aspect, the at least one portincludes injection port 272 and bleed port 274, and the sealant isinjected into interior 252 through injection port 272 and the airescapes from interior 252 through bleed port 274. The sealant is thenallowed to cure to facilitate coupling cap 250 to fastener 210.

Referring to FIG. 19-26, one example of the disclosure relates to system220 for use in covering portion 212 of fastener 210 protruding fromsurface 206 (shown in FIG. 3). The system includes cap 250 includinginterior 252, base 258 that at least partially delimits interior 252,and at least one cam 302 on interior 252. More specifically, cam 302 ison surface 262 of interior 252. In FIGS. 22 and 23, cam 302 includes anotch 304 and a tapered surface 306. System 220 also includes wall 256that at least partially delimits interior 252, seal 260 coupled to base258 to engage surface 206 (shown in FIG. 3), and at least one tab 310.In one aspect, referring to FIGS. 20 and 24, wall 256 includes at leastone port 270 formed therein, and tab 310 is coupled to fastener 210 topositively engage the at least one cam 302.

In FIG. 19, lines connecting various elements and/or components ofsystem 220 may represent mechanical, electrical, fluid, optical,electromagnetic and other couplings and/or combinations thereof.Couplings other than those depicted in FIG. 19 may also exist. Dashedlines connecting the various elements and/or components of system 220may represent couplings similar in function and purpose to thoserepresented by solid lines; however, couplings represented by the dashedlines are either selectively provided or relate to alternative oroptional aspects of the disclosure. Likewise, elements and/or componentsof system 220 represented in dashed lines represent alternative oroptional aspects of the disclosure.

Referring to FIGS. 20-22, tab 310 may be coupled to fastener 210 usingany suitable fastening mechanism. For example, in one aspect, system 220further includes a collar 312 configured to be coupled to fastener 210.Collar 312 includes at least one tab 310. In one aspect, system 220 alsoincludes retainer 288 configured to couple collar 312 to fastener 210.More specifically, retainer 288 is coupled to portion 212 of fastener210 with an interference fit to prevent movement of collar 312 alonglongitudinal axis 218 of fastener 210.

Referring to FIG. 20, in one aspect, the at least one tab 310 is spaceda distance D from surface 206 (shown in FIG. 3) to enable tab 310 toengage cam 302. More specifically, a portion 313 of collar 312 has athickness T such that tab 310 extends from surface 206 a distance D.Alternatively, in one aspect and as shown in FIGS. 24-26, the at leastone tab 310 is angled away from surface 206 to enable its engagement ofcam 302 without the use of a spacer. Surface 306 of cam 302 is radiallyinclined at substantially the same angle as tab 310 such that tab 310mates with tapered surface 306 when fully engaged therewith.

In some aspects, the at least one cam 302 either extends from surface262 of interior 252, as shown in FIG. 22, or is recessed in surface 262of interior 252, as shown in FIG. 23. For example, in one aspect andreferring to FIGS. 20-22, cam 302 includes tapered surface 306, a notch304 to positively engage the at least one tab 310, and a stopper portion308. In one aspect, tapered surface 306 faces away from base 258 of cap250 to facilitate positive engagement between tab 310 and cam 302. Theat least one cam 302 may include a plurality of cams, and tab 310 mayinclude a plurality of tabs to be received by gaps 314 formed betweenadjacent cams 302. To positively engage tab 310 and cam 302, once tabs310 are received in gaps 314, cap 250 is rotated in a direction 320. Tab310 is sized for mating with notch 304 (shown in FIG. 22) to prevent tab310 from backing out once engaged with cam 302.

Referring to FIG. 23, cam 302 is recessed in surface 262 of interior252. More specifically, cam 302 includes an axial slot 316 and atransverse slot 318 extending from axial slot 316 in a circumferentialdirection about interior 252. Transverse slot 318 also includes notch304 for positively engaging tab 310. In operation, tab 310 is insertedinto axial slot 316 as fastener 210 is covered with cap 250. Cap 250 isthen rotated in direction 320 to positively engage tab 310 and cam 302once tab 310 is received in notch 304.

A method (shown in FIG. 30) of covering portion of fastener 210protruding from surface 206 is also provided. The method includesproviding 350 cap 250 that includes wall 256, interior 252 at leastpartially delimited by wall 256, and at least one cam 302 on interior252. The method also includes coupling 352 at least one tab 310 withfastener 210, covering 354 portion 212 of fastener 210 with cap 250, androtating 356 cap 250 to engage the at least one cam 302 with the atleast one tab 310. In one aspect, rotating 356 cap 250 includespositively engaging the at least one cam 302 with the at least one tab310.

As described above, in one aspect, cap 250 includes at least one port270 extending through wall 256. In one aspect, the at least one port 270may be a single port. In one aspect, the method further includes sealingbase 258 against surface 206, creating a vacuum in interior 252, andinjecting a sealant into interior 252. In one aspect, creating thevacuum in interior 252 includes withdrawing air from interior 252through the single port. As such, withdrawing air from interior 252enables the sealant to substantially fill interior 252 by limiting theformation of air pockets in interior 252.

In one implementation, an amount of sealant to be injected into interior252 may be selected to prevent the use of excess sealant, to facilitatecleanup, and to promote a reduction in the weight of aircraft 102 (shownin FIG. 2). As such, in one aspect, injecting the sealant includesinjecting a predetermined amount of sealant into interior 252 throughthe single port. More specifically, in one aspect, injecting apredetermined amount of sealant includes determining the predeterminedamount of sealant for filling interior 252 based on a vacant volume ofinterior 252. In one aspect, the use of excess sealant is avoided bydiscontinuing to inject the sealant upon detection of a predeterminedback pressure at the single port. The predetermined back pressure may beany suitable pressure selected to indicate that interior 252 has beensubstantially filled with sealant.

Alternatively, in one aspect, the method includes sealing base 258against surface 206, injecting a sealant into interior 252 through theat least one port 270, and allowing air to escape from interior 252through the at least one port 270. In one aspect, the at least one portincludes injection port 272 and bleed port 274, and the sealant isinjected into interior 252 through injection port 272 and the airescapes from interior 252 through bleed port 274. The sealant is thenallowed to cure to facilitate coupling cap 250 to fastener 210.

This written description uses examples to disclose variousimplementations, including the best mode, and also to enable any personskilled in the art to practice the various implementations, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the disclosure is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal language of theclaims.

What is claimed is:
 1. A method of covering a portion of a fastenerprotruding from a surface with a cap that comprises a wall, an interiorat least partially delimited by the wall, and at least one cam in theinterior, the method comprising: coupling at least one tab with thefastener; covering the portion of the fastener with the cap; androtating the cap to engage the at least one cam with the at least onetab.
 2. The method in accordance with claim 1, wherein rotating the capcomprises positively engaging the at least one cam with the at least onetab.
 3. The method in accordance with claim 1, wherein the cap comprisesat least one port extending through the wall.
 4. The method inaccordance with claim 3, wherein the at least one port is a single port.5. The method in accordance with claim 4, further comprising: sealing abase of the cap against the surface; creating a vacuum in the interiorof the cap; and injecting a sealant into the interior of the cap.
 6. Themethod in accordance with claim 5, wherein creating the vacuum in theinterior of the cap comprises withdrawing air from the interior throughthe single port, extending through the wall of the cap.
 7. The method inaccordance with claim 5, wherein injecting the sealant into the interiorof the cap comprises injecting a predetermined amount of the sealant ofthe cap through the single port, extending through the wall of the cap.8. The method in accordance with claim 7, wherein injecting thepredetermined amount of the sealant into the interior of the capcomprises determining the predetermined amount of the sealant based on avacant volume of the interior of the cap.
 9. The method in accordancewith claim 5, further comprising discontinuing to inject the sealantinto the interior of the cap upon detection of a predetermined backpressure at the single port, extending through the wall of the cap. 10.The method in accordance with claim 3 further comprising: sealing a baseof the cap against the surface; injecting a sealant into the interior ofthe cap through the at least one port, extending through the wall of thecap; and allowing air to escape from the interior of the cap through theat least one port.
 11. The method in accordance with claim 10, whereinthe at least one port, extending through the wall of the cap, comprisesan injection port and a bleed port.
 12. The method in accordance withclaim 11, wherein: the sealant is injected into the interior of the capthrough the injection port, and the air escapes from the interior of thecap through the bleed port.
 13. A method of covering a portion of afastener protruding from a surface with a cap that comprises a base, aninterior at least partially delimited by the base, at least one cam inthe interior of the cap, and a wall, having at least one port extendingtherethrough, the method comprising: coupling at least one tab to thefastener; rotatably engaging the at least one cam with the tab; andsealing the base of the cap against the surface with a seal of the cap,wherein the seal is coupled to the base.
 14. The method in accordancewith claim 13, further comprising coupling a collar to the fastener,wherein the collar comprises the at least one tab.
 15. The method inaccordance with claim 14, wherein coupling the collar to the fastenercomprises coupling the collar to the fastener using a retainer.
 16. Themethod in accordance with claim 13, wherein coupling the at least onetab to the fastener comprises coupling the at least one tab to thefastener such that the at least one tab is spaced from the surface. 17.The method in accordance with claim 13, wherein rotatably engaging theat least one cam comprises rotatably engaging the at least one cam suchthat a notch formed in the at least one cam engages the at least onetab.
 18. The method in accordance with claim 13, wherein the cap furthercomprises a plurality of cams in the interior.
 19. The method inaccordance with claim 13, wherein coupling at least one tab to thefastener comprises coupling the at least one tab to the fastener suchthat the at least one tab is angled away from the surface.